<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    .box{
      width: 500px;
      height: 500px;
      background-color: #b3d4fc;
      position: absolute;
      left: 50%;
      margin-left: -250px;
    }
  </style>
</head>
<body>
<div class="box"></div>
</body>
</html>
